1. Field of the Invention
The present invention relates generally to an apparatus for facilitating the installation of individual fasteners, such as screws or the like, and more particularly, to an apparatus which is operable to releasably secure the head of an individual screw in a predetermined location relative to a rotatable bit thereby facilitating the installation of the screw into a work piece, and which further is operable to release the head of the screw from the predetermined location upon the engagement of the apparatus with the work piece.
2. Description of the Prior Art
During the construction of buildings, and in the manufacture of various articles of commerce, it is typically necessary for a worker to install numerous screws or other types of threaded fasteners into assorted work pieces by employing powered screw driving tools having various configurations and designs. In the construction of dwellings, for example, work pieces which may be joined to other objects or surfaces by threaded fasteners may include sheet-like materials such as drywall, decorative paneling, plywood subflooring and the like. These materials, of course, have different textures and also may be positioned in assorted locations and positions which may from time to time present problems with regards to installing a screw type fastener in the respective surfaces. For example, the tough texture of sheet-like materials, such as exterior-grade plywood may present difficulties in starting the threaded fastener or further, the screw may need to be driven in a nonperpendicular or angled relationship through the work piece. Moreover, and during the installation of screws or other fasteners which have a substantial length dimension, the slotted portion of the screw head will often become distorted or burred by the rotatable bit of the powered screw driver when the bit temporarily disengages from the screw head. When this event occurs, installation or removal of the screw often becomes difficult. Moreover, the aesthetic appearance of the object may be adversely affected. To prevent or otherwise inhibit this distortion or burring of a screw head, or further, to insure that the screw is being started in an appropriate fashion in the work piece, which is not provided with a pilot hole, it is often necessary to apply substantial physical force to the powered screwdriver thereby fixedly positioning the screw in tight engagement with the rotatable bit. Further, and if the screw is being installed in material which is rather tough, such as in pressure treated lumber, this physical force will need to be maintained until the screw is installed completely into the material.
Heretofore, various devices and assemblies have been constructed and incorporated into both manual and powered screw driving tools and which hold individual screws during the screw installation process. These prior art screw holding devices have generally included two categories of mechanical design. In the first design category, these prior art screw holding devices have included a powered screw driving means and a detachably mounted device for holding a plurality of screws in a ready, screw driving position. In the second design category, these prior art screw holding devices have typically included a manually operated screw driving means and which has made integral therewith, an attachment for holding individual screws.
Examples of prior art devices which may include the aforementioned screw holding devices are found in U.S. Pat. Nos. 5,207,127; 3,757,407; 4,936,169; 2,884,971; 2,774,401, 2,310,287; and 2,633,169.
Foremost among the noted deficiencies of some of these prior art screw holding devices is their apparent inability to securely hold a screw, during the installation thereof or to automatically release the screw when the screw holding device engages a work surface. More particularly, the prior art screw holding devices of the first design category automatically release an individual screw from the device prior to the complete installation of the screw. Further, the screw holding devices of the second design category typically required that a user manually disengage the individual screw from the device, such as by actuating a lever or the like. As should be understood, the prior art screw holding devices of the first design category do not hold the heads of the respective individual screws in a locked position against the rotatable bit throughout the entire screw installation cycle. Therefore, the individual screw heads may become distorted or burred during installation, unless, the user applies substantial force to the device to insure a tight, interlocking relationship between the bit and the screw head. Of course, utilizing a tool under these conditions for a prolonged period of time will eventually result in worker fatigue.
Another deficiency of the prior art screw holding devices of the second design category, as noted earlier, is that the user must manually disengage or release the screw from the device. For example, in U.S. Pat. No. 2,774,401, a screw driver is disclosed which includes a screw holding device and a screw head pressure applicator. The device is operable, by way of a pivoted lever, to cause the bit to tightly engage the screw head. In operation, a user must manually move the lever back and forth from a first, screw release position, wherein the screw head pressure applicator is disposed in a nonengaging position, which permits a screw to be loaded in the screw holding device, and a second, screw engaging position wherein the bit tightly engages the screw. This type of a device, of course, increases the total number of steps required to install a single screw, and which, when multiplied by hundreds of screws, reduces the efficiency of any manufacturing process employing same. Other prior art screw holding devices of the second design type generally require that assorted steps be taken by a user to disengage or release a screw from the device which similarly results in reduced efficiency during the manufacturing process.
Still another deficiency common to a few of the prior art screw holding devices of the first design category is the propensity for such assemblies to be heavy and cumbersome when employed in typical commercial, or consumer environments. An example of such a device is disclosed in U.S. Pat. No. 4,936,169. As should be understood, an operator of such a prior art screw holding device would typically utilize this device continually throughout a work shift, or during the course of a common home improvement project. Further, and as a general matter, power fastening tools of this same type are typically utilized during such operations at arm's length away from a user's body, or in some cases, directly above the user's head. Therefore, the weight and cumbersome characteristics of these prior art fastening tools reduces the efficiency of a user by causing fatigue.
Yet another deficiency attendant with the prior art screw holding devices of the first design category is their complexity of design. This is particularly true for the prior art screw holding device which is disclosed in U.S. Pat. No. 4,936,169. This complexity of design, as should be understood, increases the likelihood that such screw holding devices will fail, jam or otherwise malfunction during operation when they are exposed to the dust or debris which is typically generated during their use. Further, and as should be readily apparent, the complex design of these screw holding devices increases the manufacturing costs for same.
Therefore, it has long been known that it would be desirable to have an apparatus for facilitating the installation of screws, and which is particularly well suited to retain a screw in tight engagement with respect to a bit of a screw driving means, and which further is operable to automatically release the screw upon engagement of the apparatus with a work piece or surface, and wherein the apparatus is lightweight, simple in design, and may also be releasably mounted on a variety of portable powered screw driver tools, or similar devices without substantial modification of the tool or device.